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Started by Alan Fowler
Sat, 25 Apr 1998 00:00
Digital Pads - What are they?
Author: Alan Fowler
Date: Sat, 25 Apr 1998 00:00
Date: Sat, 25 Apr 1998 00:00
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1774 bytes
I've seen several references to digit pads which appear to be
part of a line card in a digital exchange.
Are these basically a PROM or similar fitted ahead of the DAC in
the codec. I assume they would have an input for the 8-bit PCM
code, a control input, and an 8-bit output to the DAC. The PROM
would contain a lookup table which would translate the input
code to the equivalent PCM code for a particular loss which
would be set by a code fed to a control port on the PROM.
That's a bit clumsy, but I hope you understanf what I mean.
The net result would be the same as having a variable resistor
pad following the DAC.
What is the range of loss available please?
When would they be used to introduce a loss? All the time, or
only in special cases?
I would appreciate any further help or information you can give.
regards, Alan.
.
My correct mail address is amfowler@melbpc.org.au
Please delete anything between the "@" and "melbpc" when replying.
,-._|\ Alan Fowler. (Alan M. Fowler FIEAust CPEng)
/ Oz \ Mail Address: PO Box 1008G, North Balwyn 3104 Vic, AUSTRALIA.
\_,--.x/ Phone: +613-9857-7128 Member, Melbourne PC User Group.
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